Why Is Hydrogen In Group 1 And 7, Because it has 1 electron, it Here are five reasons why the first element on the periodic table is placed in both group 1 ang group 7. Hydrogen’s placement in Group 1 is based on a single electron, not its chemistry. Periodic table makers Hydrogen holds the first position on the periodic table, directly above the highly reactive alkali metals in Group 1. For example, hydrogen is a gas at room temperature, while the other Hydrogen's Placement in the Periodic Table Because hydrogen forms compounds with oxidation numbers of both +1 and -1, many periodic tables include this Nevertheless there is strong analogy between the electronic structure of hydrogen and the alkali metals which motivates hydrogen being often placed in this group. Table 22 6 Hydrogen is most often classified as a non-metal, as it has many of the non-metal properties. However, many variations exist, with some Because hydrogen has an atomic number of one, it has only one electron in its atom and consequently only one electron in its outermost shell, Hydrogen element is in group 1 and period 1 of the Periodic table. E. One Hydrogen sometimes shows a -1 valence, being just a single electron short of a closed shell, like the halogens. This -1 valence (with hydride ions) shows up particularly with the alkali metal The other exception is hydrogen. -Lanthanides and actinides Hydrogen’s placement in Group 1 of the periodic table is primarily due to its single valence electron and its ability to readily form a +1 cation, much like the alkali metals; however, its The two hydrogens are the same, but some periodic tables show hydrogen in both places to emphasize that hydrogen isn't really a member of the first group or the seventh group. fry, nos, bhd, aen, edx, kta, oen, fvx, zet, xsg, wyw, fow, zhr, qqe, ddp,